A 61-Year-Old Man With Membranoproliferative Glomerulonephritis Farah Daccueil, MD, Naveed N. Masani, MD, Vivette D. D’Agati, MD, Shayan Shirazian, MD  American Journal of Kidney Diseases  Volume 70, Issue 6, Pages A16-A20 (December 2017) DOI: 10.1053/j.ajkd.2017.08.004 Copyright © 2017 National Kidney Foundation, Inc. Terms and Conditions

Figure 1 Kidney biopsy specimen. (A) Light microscopy (hematoxylin and eosin stain; original magnification, ×400) shows diffusely enlarged and hypercellular glomeruli with accentuated lobularity. There are well-developed membranoproliferative features with widespread mesangial interposition and infiltrating leukocytes. (B) Light microscopy (periodic acid–Schiff stain; original magnification, ×600) shows mesangial expansion and numerous double contours of glomerular basement membranes with ribbon-like thickenings and subendothelial deposits between some double contours. (C) Immunofluorescence (original magnification, ×400) shows granular global mesangial and glomerular capillary wall positivity (3+) for C3 only. (D) Electron microscopy (original magnification, ×6,000) shows marked, diffuse, and global increase in mesangial cell number and matrix with abundant ring-shaped mesangial dense deposits. Ribbon-like highly electron-dense deposits are identified in the lamina densa of the glomerular basement membrane and drop off into the subendothelial zones. American Journal of Kidney Diseases 2017 70, A16-A20DOI: (10.1053/j.ajkd.2017.08.004) Copyright © 2017 National Kidney Foundation, Inc. Terms and Conditions

Figure 2 Diagnostic algorithm for membranoproliferative glomerulonephritis (MPGN). Based on information in Sethi and Fervenza1 and Pickering et al.2 Abbreviations: Ab, antibody; APL, antiphospholipid syndrome; cryo, cryoglobulinemia; EM, electron microscopy; GN, glomerulonephritis; HUS, hemolytic uremic syndrome; IF, immunofluorescence; Ig, immunoglobulin; MCTD, mixed connective tissue disease; RA, rheumatoid arthritis; SLE, systemic lupus erythematosus; TMA, thrombotic microangiopathy; TTP, thrombotic thrombocytopenic purpura. American Journal of Kidney Diseases 2017 70, A16-A20DOI: (10.1053/j.ajkd.2017.08.004) Copyright © 2017 National Kidney Foundation, Inc. Terms and Conditions

Figure 3 Pathogenic alterations of the alternative complement pathway in this disease. Based on information in Sethi and Fervenza1 and Pickering et al.2 Abbreviations: CD 46, cluster of differentiation; CFHR, complement factor H-related protein; MCP, membrane cofactor protein. American Journal of Kidney Diseases 2017 70, A16-A20DOI: (10.1053/j.ajkd.2017.08.004) Copyright © 2017 National Kidney Foundation, Inc. Terms and Conditions